Tornadoes · United States · Illinois · 1986

F2 tornado, Livingston and McLean counties, Illinois, September 29, 1986

This F2 tornado ran 9.0 miles across Livingston and McLean counties on September 29, 1986, touching down at 5:34 PM CDT and reaching 50 yards wide. It killed nobody, and did $500,000 to $5 million of property damage.

The rating scale

Tracks are drawn in the color of the rating. The Fujita scale rates the damage rather than measuring the wind: the speeds are what that damage is taken to imply.

  1. F040 to 72 mph

    Light damage. Surface peeled off some roofs, gutters and siding damaged, branches broken, shallow-rooted trees pushed over.

  2. F173 to 112 mph

    Moderate damage. Roofs badly stripped, mobile homes overturned or badly damaged, exterior doors lost, windows broken.

  3. F2113 to 157 mphthis tornado

    Considerable damage. Roofs torn off well-built houses, frame homes shifted on their foundations, mobile homes destroyed, large trees snapped or uprooted, cars lifted off the ground.

  4. F3158 to 206 mph

    Severe damage. Whole stories of well-built houses destroyed, large buildings badly damaged, trains overturned, trees debarked, heavy cars lifted and thrown.

  5. F4207 to 260 mph

    Devastating damage. Well-built houses leveled, structures with weak foundations moved some distance, cars thrown and large missiles generated.

  6. F5261 to 318 mph

    Incredible damage. Strong frame houses swept off their foundations, car-sized missiles thrown more than 100 meters, steel-reinforced concrete badly damaged, high-rise buildings deformed.

  7. Unrated

    The survey recorded a tornado but could not put a number on it, most often because it crossed open country and damaged nothing a rating can be read from.

The record

Rating
F2
Date
September 29, 1986
Touchdown
5:34 PM CDT (22:34 UTC)
Path length
9.0 miles (14.5 km)
Path width
50 yards (46 m)
Deaths
0
Injuries
0
Property damage
$500,000 to $5 million
Counties
Livingston and McLean counties
Touchdown point
40.750, -88.650
Lift-off point
40.750, -88.520
Record number
712

The air that afternoon

The radiosonde launches on either side of the tornado, from the nearest station that was launching then, drawn and analyzed the way Storm Lab does: the same diagram, the same parcel and shear definitions SPC's mesoanalysis uses.

Peoria Regional, IL (KPIA), 12:00Z

10.6 hours before the tornado, 86 km from the path. September 29, 1986.

Skew-T log-pSkew-T log-p diagram, Peoria Regional, IL at 12:00Z on 1986-09-29Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 1108 joules per kilogram, CIN -54, lifted condensation level 965 meters above ground. Wind barbs in knots down the right edge.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed. The warm shading is its CAPE, the cool shading the inhibition it has to break through.
HodographHodograph, Peoria Regional, IL at 12:00Z on 1986-09-29The wind through the lowest 10 kilometers as a curve, rings every 10 meters per second labeled in knots. Zero to 1 km storm-relative helicity 111 square meters per square second, 0 to 6 km bulk shear 50 knots.19395878Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km. RM and LM are the right and left moving storms Bunkers' method gives; the shaded area is the 0 to 1 km storm-relative helicity.
Mixed-layer CAPE
1108 J/kg
Mixed-layer CIN
-54 J/kg
Surface CAPE
1150 J/kg
Mixed-layer LCL
965 m above ground
0-6 km bulk shear
50 kt
0-1 km bulk shear
36 kt
0-1 km storm-relative helicity
111 m²/s²
0-3 km storm-relative helicity
124 m²/s²
Significant tornado parameter
0.6
Supercell composite
2.2
0-3 km lapse rate
5.9 K/km

Open this sounding in Storm Lab

The surface observations

Bloomington/Norm (BMI), 41 km from the path, in the two hours either side.

Time (UTC)Temp (°F)Dew point (°F)WindGust (kt)Pressure (mb)Weather
00:00 UTC

From the Iowa Environmental Mesonet's archive of airport observations.

This ground now

The live radar over the trackEvery 1986 tornado in IllinoisEvery tornado in Illinois since 1950Warnings in force in Illinois nowThe forecast where you are

The other tornadoes of September 29, 1986

12 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
September 297:15 AM CDTF1Lincoln, OK4.0100$50,000 to $500,000
September 298:15 AM CDTF2Rogers, OK2.01001$50,000 to $500,000
September 291:55 PM CDTF1LaSalle, IL1.010$50,000 to $500,000
September 292:30 PM CDTF1Cook, IL0.15010$50,000 to $500,000
September 293:07 PM CDTF0Logan, OK0.150
September 294:30 PM EDTF2Van Buren, MI3.84001$50,000 to $500,000
September 293:58 PM CDTF2Tazewell, IL2.050$500,000 to $5 million
September 294:25 PM CDTF2Oklahoma, OK5.0100$50,000 to $500,000
September 294:30 PM CDTF2Oklahoma, OK0.173
September 296:51 PM EDTF2Genesee, MI5.6400$50,000 to $500,000
September 297:10 PM EDTF1Genesee, MI1.320$500 to $5,000
September 299:05 PM EDTF1Orleans, NY0.523$5,000 to $50,000

What this means

Ratings are the survey's, read off the damage rather than measured; the rating scale is above. Tornado counts rise through the record as reporting improved, so a year in the 1950s is not comparable with one today except for the strongest tornadoes, which were always noticed.

Sources

NOAA Storm Prediction Center tornado database, 1950-2025, the official record kept by NOAA's Storm Prediction Center.